lib/componentlib.class.php

   1 <?php  //$Id$
   2
   3 ///////////////////////////////////////////////////////////////////////////
   4 //                                                                       //
   5 // NOTICE OF COPYRIGHT                                                   //
   6 //                                                                       //
   7 // Moodle - Modular Object-Oriented Dynamic Learning Environment         //
   8 //          http://moodle.com                                            //
   9 //                                                                       //
  10 // Copyright (C) 2001-3001 Martin Dougiamas        http://dougiamas.com  //
  11 //           (C) 2001-3001 Eloy Lafuente (stronk7) http://contiento.com  //
  12 //                                                                       //
  13 // This program is free software; you can redistribute it and/or modify  //
  14 // it under the terms of the GNU General Public License as published by  //
  15 // the Free Software Foundation; either version 2 of the License, or     //
  16 // (at your option) any later version.                                   //
  17 //                                                                       //
  18 // This program is distributed in the hope that it will be useful,       //
  19 // but WITHOUT ANY WARRANTY; without even the implied warranty of        //
  20 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         //
  21 // GNU General Public License for more details:                          //
  22 //                                                                       //
  23 //          http://www.gnu.org/copyleft/gpl.html                         //
  24 //                                                                       //
  25 ///////////////////////////////////////////////////////////////////////////
  26
  27 // This library includes all the necessary stuff to use the one-click
  28 // download and install feature of Moodle, used to keep updated some
  29 // items like languages, pear, enviroment... i.e, components.
  30 //
  31 // It has been developed harcoding some important limits that are
  32 // explained below:
  33 //    - It only can check, download and install items under moodledata.
  34 //    - Every downloadeable item must be one zip file.
  35 //    - The zip file root content must be 1 directory, i.e, everything
  36 //      is stored under 1 directory.
  37 //    - Zip file name and root directory must have the same name (but
  38 //      the .zip extension, of course).
  39 //    - Every .zip file must be defined in one .md5 file that will be
  40 //      stored in the same remote directory than the .zip file.
  41 //    - The name of such .md5 file is free, although it's recommended
  42 //      to use the same name than the .zip (that's the default
  43 //      assumption if no specified).
  44 //    - Every remote .md5 file will be a comma separated (CVS) file where each
  45 //      line will follow this format:
  46 //        - Field 1: name of the zip file (without extension). Mandatory.
  47 //        - Field 2: md5 of the zip file. Mandatory.
  48 //        - Field 3: whatever you want (or need). Optional.
  49 //    -Every local .md5 file will:
  50 //        - Have the zip file name (without the extension) plus -md5
  51 //        - Will reside inside the expanded zip file dir
  52 //        - Will contain the md5 od the latest installed component
  53 // With all these details present, the process will perform this tasks:
  54 //    - Perform security checks. Only admins are allowed to use this for now.
  55 //    - Perform server checks. fopen must allow to open remote URLs.
  56 //    - Read the .md5 file from source (1).
  57 //    - Extract the correct line for the .zip being requested.
  58 //    - Compare it with the local .md5 file (2).
  59 //    - If different:
  60 //        - Download the newer .zip file from source.
  61 //        - Calculate its md5 (3).
  62 //        - Compare (1) and (3).
  63 //        - If equal:
  64 //            - Delete old directory.
  65 //            - Uunzip the newer .zip file.
  66 //            - Create the new local .md5 file.
  67 //            - Delete the .zip file.
  68 //        - If different:
  69 //            - ERROR. Old package won't be modified. We shouldn't
  70 //              reach here ever.
  71 //    - If fopen is not available, a message text about how to do
  72 //      the process manually (remotedownloadnotallowed) must be
  73 //      built to explain it.
  74 //
  75 // General Usage:
  76 //
  77 // To install one component:
  78 //
  79 //     require_once($CFG->libdir.'/componentlib.class.php');
  80 //     if ($cd = new component_installer('http://download.moodle.org', 'lang16',
  81 //                                       'es_utf8.zip', 'languages.md5', 'lang')) {
  82 //         $status = $cd->install(); //returns ERROR | UPTODATE | INSTALLED
  83 //         switch ($status) {
  84 //             case ERROR:
  85 //                 if ($cd->get_error() == 'remotedownloadnotallowed') {
  86 //                     $a = new stdClass();
  87 //                     $a->url = 'http://download.moodle.org/lang16/es_utf8.zip';
  88 //                     $a->dest= $CFG->dataroot.'/lang';
  89 //                     error(get_string($cd->get_error(), 'error', $a));
  90 //                 } else {
  91 //                     error(get_string($cd->get_error(), 'error'));
  92 //                 }
  93 //                 break;
  94 //             case UPTODATE:
  95 //                 //Print error string or whatever you want to do
  96 //                 break;
  97 //             case INSTALLED:
  98 //                 //Print/do whatever you want
  99 //                 break;
 100 //             default:
 101 //                 //We shouldn't reach this point
 102 //         }
 103 //     } else {
 104 //         //We shouldn't reach this point
 105 //     }
 106 //
 107 // To switch of component (maintaining the rest of settings):
 108 //
 109 //     $status = $cd->change_zip_file('en_utf8.zip'); //returns boolean false on error
 110 //
 111 // To retrieve all the components in one remote md5 file
 112 //
 113 //     $components = $cd->get_all_components_md5();  //returns boolean false on error, array instead
 114 //
 115 // To check if current component needs to be updated
 116 //
 117 //     $status = $cd->need_upgrade();  //returns ERROR | UPTODATE | NEEDUPDATE
 118 //
 119 // To get the 3rd field of the md5 file (optional)
 120 //
 121 //     $field = $cd->get_extra_md5_field();  //returns string (empty if not exists)
 122 //
 123 // For all the error situations the $cd->get_error() method should return always the key of the
 124 // error to be retrieved by one standard get_string() call against the error.php lang file.
 125 //
 126 // That's all!
 127
 128 // Some needed constants
 129 define('ERROR',           0);
 130 define('UPTODATE',        1);
 131 define('NEEDUPDATE',      2);
 132 define('INSTALLED',       3);
 133
 134 /**
 135  * This class is used to check, download and install items from
 136  * download.moodle.org to the moodledata directory. It always
 137  * return true/false in all their public methods to say if
 138  * execution has ended succesfuly or not. If there is any problem
 139  * its getError() method can be called, returning one error string
 140  * to be used with the standard get/print_string() functions.
 141  */
 142 class component_installer {
 143
 144     var $sourcebase;   /// Full http URL, base for downloadeable items
 145     var $zippath;      /// Relative path (from sourcebase) where the
 146                        /// downloadeable item resides.
 147     var $zipfilename;  /// Name of the .zip file to be downloaded
 148     var $md5filename;  /// Name of the .md5 file to be read
 149     var $componentname;/// Name of the component. Must be the zip name without
 150                        /// the extension. And it defines a lot of things:
 151                        /// the md5 line to search for, the default m5 file name
 152                        /// and the name of the root dir stored inside the zip file
 153     var $destpath;     /// Relative path (from moodledata) where the .zip
 154                        /// file will be expanded.
 155     var $errorstring;  /// Latest error produced. It will contain one lang string key.
 156     var $extramd5info; /// Contents of the optional third field in the .md5 file.
 157     var $requisitesok; /// Flag to see if requisites check has been passed ok.
 158
 159     var $cachedmd5components; /// Array of cached components to avoid to
 160                               /// download the same md5 file more than once per request.
 161
 162     /**
 163      * Standard constructor of the class. It will initialize all attributes.
 164      * without performing any check at all.
 165      *
 166      * @param string Full http URL, base for downloadeable items
 167      * @param string Relative path (from sourcebase) where the
 168      *               downloadeable item resides
 169      * @param string Name of the .zip file to be downloaded
 170      * @param string Name of the .md5 file to be read (default '' = same
 171      *               than zipfilename)
 172      * @param string Relative path (from moodledata) where the .zip file will
 173      *               be expanded (default='' = moodledataitself)
 174      * @return object
 175      */
 176     function component_installer ($sourcebase, $zippath, $zipfilename, $md5filename='', $destpath='') {
 177
 178         $this->sourcebase   = $sourcebase;
 179         $this->zippath      = $zippath;
 180         $this->zipfilename  = $zipfilename;
 181         $this->md5filename  = $md5filename;
 182         $this->componentname= '';
 183         $this->destpath     = $destpath;
 184         $this->errorstring  = '';
 185         $this->extramd5info = '';
 186         $this->requisitesok = false;
 187         $this->cachedmd5components = array();
 188
 189         $this->check_requisites();
 190     }
 191
 192     /**
 193      * This function will check if everything is properly set to begin
 194      * one installation. It'll check for fopen wrappers enabled and
 195      * admin privileges. Also, it will check for required settings
 196      * and will fill everything as needed.
 197      *
 198      * @return boolean true/false (plus detailed error in errorstring)
 199      */
 200     function check_requisites() {
 201         global $CFG;
 202
 203         $this->requisitesok = false;
 204
 205         /// Check for fopen remote enabled
 206         if (!ini_get('allow_url_fopen')) {
 207             $this->errorstring='remotedownloadnotallowed';
 208             return false;
 209         }
 210     /// Check that everything we need is present
 211         if (empty($this->sourcebase) || empty($this->zippath) || empty($this->zipfilename)) {
 212             $this->errorstring='missingrequiredfield';
 213             return false;
 214         }
 215     /// Check for correct sourcebase (this will be out in the future)
 216         if ($this->sourcebase != 'http://download.moodle.org') {
 217             $this->errorstring='wrongsourcebase';
 218             return false;
 219         }
 220     /// Check the zip file is a correct one (by extension)
 221         if (stripos($this->zipfilename, '.zip') === false) {
 222             $this->errorstring='wrongzipfilename';
 223             return false;
 224         }
 225     /// Check that exists under dataroot
 226         if (!empty($this->destpath)) {
 227             if (!file_exists($CFG->dataroot.'/'.$this->destpath)) {
 228                 $this->errorstring='wrongdestpath';
 229                 return false;
 230             }
 231         }
 232     /// Calculate the componentnamea
 233         $pos = stripos($this->zipfilename, '.zip');
 234         $this->componentname = substr($this->zipfilename, 0, $pos);
 235     /// Calculate md5filename if it's empty
 236         if (empty($this->md5filename)) {
 237             $this->md5filename = $this->componentname.'.md5';
 238         }
 239     /// Set the requisites passed flag
 240         $this->requisitesok = true;
 241         return true;
 242     }
 243
 244     /**
 245      * This function will perform the full installation if needed, i.e.
 246      * compare md5 values, download, unzip, install and regenerate
 247      * local md5 file
 248      *
 249      * @return int ERROR | UPTODATE | INSTALLED
 250      */
 251     function install() {
 252
 253         global $CFG;
 254
 255     /// Check requisites are passed
 256         if (!$this->requisitesok) {
 257             return ERROR;
 258         }
 259     /// Confirm we need upgrade
 260         if ($this->need_upgrade() === ERROR) {
 261             return ERROR;
 262         } else if ($this->need_upgrade() === UPTODATE) {
 263             $this->errorstring='componentisuptodate';
 264             return UPTODATE;
 265         }
 266     /// Create temp directory if necesary
 267         if (!make_upload_directory('temp', false)) {
 268              $this->errorstring='cannotcreatetempdir';
 269              return ERROR;
 270         }
 271     /// Download zip file and save it to temp
 272         $source = $this->sourcebase.'/'.$this->zippath.'/'.$this->zipfilename;
 273         $zipfile= $CFG->dataroot.'/temp/'.$this->zipfilename;
 274         if ($contents = file_get_contents($source)) {
 275             if ($file = fopen($zipfile, 'w')) {
 276                 if (!fwrite($file, $contents)) {
 277                     fclose($file);
 278                     $this->errorstring='cannotsavezipfile';
 279                     return ERROR;
 280                 }
 281             } else {
 282                 $this->errorstring='cannotsavezipfile';
 283                 return ERROR;
 284             }
 285             fclose($file);
 286         } else {
 287             $this->errorstring='cannotdownloadzipfile';
 288             return ERROR;
 289         }
 290     /// Calculate its md5
 291         $new_md5 = md5($contents);
 292     /// Compare it with the remote md5 to check if we have the correct zip file
 293         if (!$remote_md5 = $this->get_component_md5()) {
 294             return ERROR;
 295         }
 296         if ($new_md5 != $remote_md5) {
 297             $this->errorstring='downloadedfilecheckfailed';
 298             return ERROR;
 299         }
 300     /// Move current revision to a safe place
 301         $destinationdir = $CFG->dataroot.'/'.$this->destpath;
 302         $destinationcomponent = $destinationdir.'/'.$this->componentname;
 303         @remove_dir($destinationcomponent.'_old');     //Deleting possible old components before
 304         @rename ($destinationcomponent, $destinationcomponent.'_old');  //Moving to a safe place
 305     /// Unzip new version
 306         if (!unzip_file($zipfile, $destinationdir, false)) {
 307         /// Error so, go back to the older
 308             @remove_dir($destinationcomponent);
 309             @rename ($destinationcomponent.'_old', $destinationcomponent);
 310             $this->errorstring='cannotunzipfile';
 311             return ERROR;
 312         }
 313     /// Delete old component version
 314         @remove_dir($destinationcomponent.'_old');
 315     /// Create local md5
 316         if ($file = fopen($destinationcomponent.'/'.$this->componentname.'.md5', 'w')) {
 317             if (!fwrite($file, $new_md5)) {
 318                 fclose($file);
 319                 $this->errorstring='cannotsavemd5file';
 320                 return ERROR;
 321             }
 322         } else  {
 323             $this->errorstring='cannotsavemd5file';
 324             return ERROR;
 325         }
 326         fclose($file);
 327     /// Delete temp zip file
 328         @unlink($zipfile);
 329
 330         return INSTALLED;
 331     }
 332
 333     /**
 334      * This function will detect if remote component needs to be installed
 335      * because it's different from the local one
 336      *
 337      * @return int ERROR | UPTODATE | NEEDUPDATE
 338      */
 339     function need_upgrade() {
 340
 341     /// Check requisites are passed
 342         if (!$this->requisitesok) {
 343             return ERROR;
 344         }
 345     /// Get local md5
 346         $local_md5 = $this->get_local_md5();
 347     /// Get remote md5
 348         if (!$remote_md5 = $this->get_component_md5()) {
 349             return ERROR;
 350         }
 351     /// Return result
 352        if ($local_md5 == $remote_md5) {
 353            return UPTODATE;
 354        } else {
 355            return NEEDUPDATE;
 356        }
 357     }
 358
 359     /**
 360      * This function will change the zip file to install on the fly
 361      * to allow the class to process different components of the
 362      * same md5 file without intantiating more objects.
 363      *
 364      * @param string New zip filename to process
 365      * @return boolean true/false
 366      */
 367     function change_zip_file($newzipfilename) {
 368
 369         $this->zipfilename = $newzipfilename;
 370         return $this->check_requisites();
 371     }
 372
 373     /**
 374      * This function will get the local md5 value of the installed
 375      * component.
 376      *
 377      * @return string md5 of the local component (false on error)
 378      */
 379     function get_local_md5() {
 380         global $CFG;
 381
 382     /// Check requisites are passed
 383         if (!$this->requisitesok) {
 384             return false;
 385         }
 386
 387         $return_value = 'needtobeinstalled';   /// Fake value to force new installation
 388
 389     /// Calculate source to read
 390        $source = $CFG->dataroot.'/'.$this->destpath.'/'.$this->componentname.'/'.$this->componentname.'.md5';
 391     /// Read md5 value stored (if exists)
 392        if (file_exists($source)) {
 393            if ($temp = file_get_contents($source)) {
 394                $return_value = $temp;
 395            }
 396         }
 397         return $return_value;
 398     }
 399
 400     /**
 401      * This function will download the specified md5 file, looking for the
 402      * current componentname, returning its md5 field and storing extramd5info
 403      * if present. Also it caches results to cachedmd5components for better
 404      * performance in the same request.
 405      *
 406      * @return mixed md5 present in server (or false if error)
 407      */
 408     function get_component_md5() {
 409
 410     /// Check requisites are passed
 411         if (!$this->requisitesok) {
 412             return false;
 413         }
 414     /// Get all components of md5 file
 415         if (!$comp_arr = $this->get_all_components_md5()) {
 416             $this->errorstring='cannotdownloadcomponents';
 417             return false;
 418         }
 419     /// Search for the componentname component
 420         if (empty($comp_arr[$this->componentname]) || !$component = $comp_arr[$this->componentname]) {
 421              $this->errorstring='cannotfindcomponent';
 422              return false;
 423         }
 424     /// Check we have a valid md5
 425         if (empty($component[1]) || strlen($component[1]) != 32) {
 426             $this->errorstring='invalidmd5';
 427             return false;
 428         }
 429     /// Set the extramd5info field
 430         if (!empty($component[2])) {
 431             $this->extramd5info = $component[2];
 432         }
 433         return $component[1];
 434     }
 435
 436     /**
 437      * This function allows you to retrieve the complete array of components found in
 438      * the md5filename
 439      *
 440      * @return array array of components in md5 file or false if error
 441      */
 442     function get_all_components_md5() {
 443
 444     /// Check requisites are passed
 445         if (!$this->requisitesok) {
 446             return false;
 447         }
 448
 449     /// Initialize components array
 450         $comp_arr = array();
 451
 452     /// Define and retrieve the full md5 file
 453         $source = $this->sourcebase.'/'.$this->zippath.'/'.$this->md5filename;
 454
 455     /// Check if we have downloaded the md5 file before (per request cache)
 456         if (!empty($this->cachedmd5components[$source])) {
 457             $comp_arr = $this->cachedmd5components[$source];
 458         } else {
 459         /// Not downloaded, let's do it now
 460             $availablecomponents = array();
 461             if ($fp = fopen($source, 'r')) {
 462             /// Read from URL, each line will be one component
 463                 while(!feof ($fp)) {
 464                     $availablecomponents[] = split(',', fgets($fp,1024));
 465                 }
 466                 fclose($fp);
 467             /// If no components have been found, return error
 468                 if (empty($availablecomponents)) {
 469                     $this->errorstring='cannotdownloadcomponents';
 470                     return false;
 471                 }
 472             /// Build an associative array of components for easily search
 473             /// applying trim to avoid linefeeds and other...
 474                 $comp_arr = array();
 475                 foreach ($availablecomponents as $component) {
 476                 /// Avoid sometimes empty lines
 477                     if (empty($component[0])) {
 478                         continue;
 479                     }
 480                     $component[0]=trim($component[0]);
 481                     $component[1]=trim($component[1]);
 482                     if (!empty($component[2])) {
 483                         $component[2]=trim($component[2]);
 484                     }
 485                     $comp_arr[$component[0]] = $component;
 486                 }
 487             /// Cache components
 488                 $this->cachedmd5components[$source] = $comp_arr;
 489             } else {
 490             /// Return error
 491                 $this->errorstring='cannotdownloadcomponents';
 492                 return false;
 493             }
 494         }
 495     /// If there is no commponents, error
 496         if (empty($comp_arr)) {
 497              $this->errorstring='cannotdownloadcomponents';
 498              return false;
 499         }
 500         return $comp_arr;
 501     }
 502
 503     /**
 504      * This function returns the errorstring
 505      *
 506      * @return string the error string
 507      */
 508     function get_error() {
 509         return $this->errorstring;
 510     }
 511
 512     /** This function returns the extramd5 field (optional in md5 file)
 513      *
 514      * @return string the extramd5 field
 515      */
 516     function get_extra_md5_field() {
 517         return $this->extramd5info;
 518     }
 519
 520 } /// End of component_installer class
 521
 522 ?>